Carburetor



0. SILLS CARBURETOR Sept. 10, 1929.

Filed g- 1926 I 2 Sheets-Sheet 1 QQVILLE -5|LL5. LIXEWOR.

ATTozNcys O. SILLS CARBURETOR Sept-10, 1929.

Filed. Aug. 16, l926 2 Sheets-Sheet 2 ul rlllllln ATTORNEYS.

uid fuel is mixed with air in such varying Patented Sept. 10, 1929.

UNITED STATES PATENT OFFICE.

ORVILLE BILLS, OI OTTAWA, ONTARIO, CANADA, ABSIGNOR O35 TWO-FIFTHS TO THOMAS LEWIS CORY, OI OTTAWA, ONTARIO, CANADA.

OARIBUZ BETOB.

Application filed August 16, 1826. Serial No. 120,586.

This invention relates to carburetors for internal combustion engines and has for Its obect to prov1de a carburetor in which the liqproportions as will result in improved operation of the engine at all points in its range of s cod. and under various loads. The inventlon, moreover, effects economy of fuel consumption and diminishes the production of carbon deposits in the cylinders of the engine, decarbonizes cylinders and spark plugs at high engine speeds and also diminishes 'crank case dilution. Adjustment is simple and within scope of an unskilled driver.

According to the present invention the carburetor comprises a liquid fuel supply chamber, a plurality of nozzles in communication with said member, a main throttle valve common to all of said nozzles, auxiliary throttle valves for said nozzles and means connecting said auxiliary throttle valves with one another and with the main throttle valve so that progressive opening of said main valve causes successive opening of said auxiliary valves.

' The invention comprises further features which will be described hereinafter and pointed out more particularly in the appended claims.

Referring now to the accompanying drawingsfivhich illustrate by way of example one convenient embodiment of the invention Figure 1 is a side elevation,

Figure 2 is a section substantially on the line 2-2 of Figure 1,

Figure 3 is a sectional elevation on line 3-3 of Figure 2, v

Figure 4 is a plan view,

Figure 5 is an elevation showing the carburetor' on the reverse side from that shown in Figure 1,

Figure 6 is an end elevation partially in section on line 6-6 of Figure 5,

Figure 7 is a sectional plan view of the float chamber control mechanism on line 7-7 of Figure 5, Figure 8 is a plan view partially in section on line 8--8 of Figure 1 with s rings and chains omitted for clearness of illustration and Figure 9 is a perspective view of a detail.

The body of the carburetor is illustrated as comprising a main casting 10 which encloses or carries the fuel injection and mixing devices, and a casting 11 which forms a float chamber. The main casting 10 is hollow and is preferably square in cross section towards its lower end and of circular cross-section at its upper end. The top of the casting 10 is formed with a perforated flange 12 by means of which the carburetor can be connected to the engine induction manifold. Towards its lower end the castin 10 is provided with a branch 13 which is a apted to be connected to an air inlet pipe, not shown. 4 05 The casting 11 is secured to the casting 10 by means of screws 14 which pass through holes in an extension 15 of the casting 11 and into inwardly projecting lugs or extensions 16 on the bottom of casting 10. 7

The casting 10 is provided interiorly with two shoulders 17 and 17 between which is formed a vertical rectangular passage 18. The shoulders 17 are formed with rows of three vertical bores 19, 20, 21 and 22, 23, 24, 7

respectively. Projecting tightly into the 'the depending iportions of the tubes being in the ath of air owing into the casing 10 from the .ranch 13, one eighth of the upper portions of the tubes being internally bevelled. Projecting up into the tubes 25, and coaxial therewith, are small nozzles 26 which are mounted in recesses in the extension 15 of casting 11 and which terminate at their upper ends within the bevelled upper ends of the tubes 25. Needle .valves 27 reject up into all the nozzles 26 and are a opted to coact with annular ridges 28 which restrict the area of the nozzles 26 at approximately the normal level of the gasoline in the float chamber 11. The lower extremities of the needle valves 27 extend through screw threaded bosses 29 on the extension 15, and are welded or otherwise secured to screw threaded caps 30 which coact with bosses 29 to rovide means of adjustment for the valves 2 in relation to the restrictions 28.

The stand nozzles 26 in bores 19 and 22' or screw 32, the nozzles in bores 20 and 23 and in bores 21 and 24 being similarly connected to the float chamber.

In the upper circular part of casting 10 a disc throttle valve 32 is mounted in a slit in a shaft 33, set screws 34 being provided to secure the valve 32 to the shaft. To one end of the shaft 33 is secured a toothed sector 35 adapted to receive rotary movement from an idler pinion 36 which meshes with a sector 37 carried by a lever 38 which is adapted to be operated by the usual throttle lever or pedal. The sector 37 is rigidly mounted on a shaft 39 which extends through a bore in the shoulder 17 which bore intersects the axes of vertical bores 19, 20 and 21. Mounted on shaft 39 across the bores 19, 20 and 21 is a multiple rectangular throttle valve 40, 55 and 56. V

The lever 38 is joined by a flexible connection, for example, a chain 41, to a lever 42 which is normally maintained against a stop 43 by means of a tension spring 44. The lever 42 is rigidly mounted on a short spindle 45 which carries a circular throttle disc 46 arranged in the vertical bore 22.

The Bore 24, as shown, is provided with a circular throttle disc 47 carried by a short shaft 48 on the outer end of which a lever 49 is mounted, this lever being normally main tained against a stop 50 by a tension spring 51, and connected by a normally slack chain or e uivalent connection 52 to a lever 53 carried y the end of the main throttle shaft 33.

Discs 54 are mounted on the shaft 39 to isolate the bores 19, 20 and 21 from each other and to prevent leakage therefrom. These three throttles 40, 55 and 56 are adapted to rotate as a unit in the same plane in a transverse bore 57 which is of larger diameter than any of the vertical bores 19, 20 and 21 and the axis of the transverse bore intersects the axes of the vertical bores. The outer end of bore 57 is closed by a bushing 58 which forms a bearing for the shaft 39 and also provides a means for introducing and removing the throttles 40, 55 and 56. The vertical bore 21 is of largerdiameter than the bore 20 and 20 is larger than 19, so it will be seen that when the shaft 39 is rotated the throttle valve 56 will open by passing the intersection of bores 57 and 21 before the throttle 55 will open by passing the intersection of bores 57 and 20 and 20 will open before 19. Considering bores 20 and 21 tobe partly open and bore 19 slightly open, the opening of the discthrottled bore 22 commences when the slack of the flexible connection 41 has been taken up. Flexiblev connection 52 has more slack than 41 and imparts motion to disc throttle 47 later than the initial opening of bore 22- It will be clear that the employment of relatively different lengths of levers 38, 42, 49 and 53 will impart different rates of motion to disc throttles 46 and 47 and if these levers be shortened consecutively in the present order all rectangular and disc throttles including the main throttle may .be fully opened at the same time. I

A choke valve 63 may be mounted in the branch 13 and operated by a lever 64 and the customary choke rod, not shown.

Any suitable means may be provided for maintaining and controlling the level of fuel in the chamber 11, the illustrated form con" sisting of a hollow metal or cork float 65 carried by a lever 66 which is rigidly connected to a rod 67 having a left-handed screwthread 68 engaging a correspondingly threaded passage in a stationary member 69 which is slidably mounted in a boss 70 on the casting 11. The inner end of rod 67 projects into the interior of a hollow cylindrical member 71 screwed into an aperture in the casting 11, and containing a plunger 72 carrying a needle valve 73. The valve coacts with a seat at the inner end of a central bore 74 in a nipple 75 which is screwed into the member 71 and has a screw-thread 76 for the attachment of a liquid fuel supply pipe, not shown. A light compression spring 77 tends to unseat the valve and acts to maintain the plunger 72 in contact with the rod 67. The hollow member 71 is perforated at 78 to enable fuel to pass from the bore 74 into the float chamber when the valve 73 is opened by the descent of the float and consequent left hand axial movement of the rod 67. Coarse adjustment of the needle valve to provide desired fuel level in float chamber may be effected by rotation of a packing cap 79 and fine adjustments by rotation of a finely threaded ring 80. A screw-driver slot 81 is provided to enable the member 69 to be held stationary While the washer is being rotated. The end of the cap 79 is provided with a series of tapped holes to receive one or more screws 82 which retain the ring 80 in adjusted position.

The float chamber casting 11 is furnished with a cover plate 83 which is held in position by screws 84 engagin tapped holes in lugs 85 on the casing 11. xtending through a hole is a plunger 86 urged upwardly by a spring 87, the upward movement being limited by a pin 88. By depressing the plunger 86 the fioat 65 may be forced down and the needle valve 73 thereby opened when itis desired to flood the carburetor. The bottom wall of the float chamber 11 is provided with a suitable drain closed by a plug as shown at 89.

Within the space 18 between the shoulders 17 and 17 of casting 10 is arranged an inclined frame 90 (see Figures 3, 8 and 9) held in position by screws 91. A rectangular valve 92 of a size just suliicient to be seated on said frame, is rigidly carried by a spindle 93 which is mounted in hearings in the casting 10. The outer end of spindle 93 carries a lever 94 and a tension spring 95 normally maintains the valve 92 yieldingly in contact with the frame 90, thus closing the space 18. Means as indicated at 96 may be provided for adjusting the tension of the spring 95, and a housing is preferably provided to enclose the spring 95 and lever 94 as indicated in dotted lines at 97.

The operation of the carburetor is as follows The float operated valve 73 keeps the liquid fuel at about the level shown in Figure 3 and through the passages 31 the nozzles 26 are filled with fuel to the neighbourhood of the nozzles formed by the restrictions 28.

Fuel spray is induced at the unthrottled nozzles by suction from an engine in motion and is mixed in the upper part of chamber 10 w1th air drawn from the inlet branch 13 by way of the nozzle passages and the air passage 18. Manual control of engine suction determines the engine speed and such control is exercised by the main throttle valve 32'. Lever 38 operates throttle valve 32, throttle valves 56, and 40, and disc throttles 46 and 47, which open in succession in the order just enumerated. Assume that with a given load and with all throttle valves and passage 18 fully opened the engine is running at full speed. Then on addition of work load to the engine all throttle valves may be manually held open, but passage 18 will close automatically as the engine speed and suction will be reduced by the increased load on the engine, and all air from branch 13 will then be directed by way of the annular nozzle passages only. Due to the isolation of passage 18 from the nozzle passages, calibration of nozzles, nozzle passages and passage 18, may be made such that a proper adjustment of these elements at full engine speed isalso a proper adjustment at maximum engine work load, and also at all intermediate points of the engines range of speed. The function of the tubes 25 is to direct air to their respective nozzles, and also to prevent engine suction when the choke valve 63 is open from drawing fuel from any throttled nozzle down through its air passage and up into the engine through either valve 92 or through any of the unthrottled nozzle passages.

It will be understood that the foregoing description is given by way of example only and that various modifications may be made without departing from the spirit of the in vention as defined in the appended claims. For example, the order in which the auxiliary throttles open 'is immaterial, as is also the means for coupling the auxiliary throttles to the main throttle. Any suitable mechanical connections may be provided which will have the requisite amount of lost motion so that the auxiliary throttles are opened in succession as the main throttle is opened, and close successively as the main throttle is closed.

For instance, the plurality of nozzles will be restricted to such numbers as may be re quired for demanded performance of different motors in keeping with size of cylinder bore, length of piston stroke, vacuum strength, and consequent power rate.

In the claims the term simple nozzle defines a fuel spray nozzle as one not complicated, integrally therewith, by a fuel well, an air-bleeding device, or other apparatus to effect the scale of fuel delivery.

In certain of the appended claims it is stated that means are provided closely surrounding the nozzles and extending a substantial distance below the normal fuel level forming a restricted annular air passage, r

around each nozzle.- In this connection it may be mentioned, by Way of example, that good results are obtained when the tubes 25 depend two inches below the restrictions 28 and an annular space of three thirty-seconds of an inch is provided between the tubes 25 and nozzles 26. These dimensions may vary with the size of the carburetor and if the tubes 25 depended three inches the annular spaces would be made about one quarter of an inch.

The top of the nozzles may terminate from one sixteenth to one quarter of an inch above the fuel level, depending upon the size of the carburetor.

What I claim is:

1. A carburetor comprising a casing having an inlet and outlet, a main throttle valve adjacent said outlet, a plurality of parallel bores in said casing, similar nozzles projecting up into each of said bores to a level substantially above the normal fuel level, auxiliary throttle valves in said bores and arranged between the free ends of said nozzles and said main throttle, means closely surrounding each of said nozzles and extending a substantial distance below the normal fuel level forming a restricted annular air passage surrounding each nozzle, anair passage extending parallel to said bores and an automatic, spring loaded valve in said last mentioned air passage.

2. In a carburetor, a casing, a plurality of bores of different diameters in said casing, a nozzle projecting up into each of said bores, a transverse bore of larger diameter than any of said parallel bores and intersecting the axes thereof, a shaft in said transverse bore, a rectangular throttle valve mounted on said shaft over each nozzle, and means for manually rotating said shaft and throttle valves, said bores being opened in succession as the edges of the throttlevalves pass over the lines of juncture of the parallel bores and the transverse bore.

3. Acarburetor comprising a casing having an inlet and an outlet, a main throttle valve adjacent said outlet, a pair of shoulders in said casing, bores in said shoulders, auxiliary throttle valves in said bores, a plurality of similar nozzles projecting up into said bores to a point substantially above the fuel level, means closely surrounding each of said nozzles and extending a substantial distance below the normal fuel level forming a restricted annular air passage around each nozzle, a spring loaded valve arranged between said shoulders, and means interconnecting said main and auxiliary throttle valves whereby the auxiliary valves open successively as the main valve is progressively opened and reach their fully 0 en positions substantially simultaneously with the main valve.

4. A carburetor comprising a casing having an inlet and an outlet, a main throttle valve adjacent said outlet, a pair of spaced shoulders between said inlet and main throt-' tle valve, bores in said shoulders, tubes depending from said bores and extending across the axis of said inlet, simple tubular nozzles having restrictions adjacent their up per ends and extending to a point substantially above the fuel level, needle valves coacting with said restrictions, a loaded valve between said shoulders, auxiliary throttle valves in said bores above said nozzles, and means for interconnecting said throttle valves so that progressive opening of the main throttle is accompanied by successive opening of said auxiliary valves, said tubes closely surrrounding said nozzles and extending a substantial distance below the normal fuel level forming a restricted annular air passage around each nozzle.

5. A carburetor comprising in combination a substantially constant level chamber, a hollow casing having an air inlet and a fuel mixture outlet, bores in said casing, nozzles projecting upwardly into said bores, to a level substantially above the normal fuel level, and communicating with said chamber, a main throttle valve adjacent said outlet, auxiliary throttle valves in said bores between said nozzles andesaid main throttle valve, means connecting said auxiliary throttle valves with one another and with the main throttle valve, so that progressive opening of said main valve causes successive opening of said auxiliary valves, and means closely surrounding eachof said nozzles and extending a substantial distance below the normal fuel level forming a restricted annular air passage around each nozzle.

In testimony whereof I aflix my signature.

ORVILLE SILLS. 

